.... I would have thought that Phoenix would try to reconnect on it's own when the network drops out.
For me Phoenix does reconnect. If I pull my LAN cable out of the computer the miner becomes idle after some seconds. When I connect the cable again with the computer the miner starts after less then one minute to work again. This is with Phoenix-files from yesterday downloaded from github.
I wonder if it depends on how the connection goes down. In my case my LAN still works, so the miner still has a good network connection, but at the gateway the connection drops, so Phoenix cannot talk to the pool server. It just stops and never recovers. I had it in this state for 24 hours a few days back, but today it's been short 20 minute ISP issues. That why I wrote a script to detect the utilization dropping to 0.
Well, for now my ISP has cleared up the issues pretty much. But I keep my "minewatch" script running just in case since it will catch and restart Phoenix for me.